Although the vast majority of patients who suffer from venous or arterial thrombosis have haemostatic systems that fall within the "normal" range of routine screening tools such as PT, aPTT, and factor assays, thrombosis is the major cause of death in Western countries. In contrast, the propensity to bleed (i.e., hemophilia) is more easily diagnosed by traditional assay methodology yet the extent of the pathology and the clinical management of these individuals is not accurately portrayed by these same assays. Para vivo models of blood coagulation developed at the University of Vermont have clearly demonstrated a correlation between an individual's potential to generate thrombin and several haemostatic defects. The assay system utilized in these studies is based on a tissue factor initiated whole blood clotting technique in which thrombin generation is monitored via quantitation of thrombin-antithrombin m complex formation. We propose to modify and make clinically accessible this existing comprehensive method of monitoring the haemostatic competence of whole blood. In phase I of this proposal, we will conduct studies to demonstrate the feasibility of commercializing this research based assay. The successful completion of this Phase I proposal will demonstrate the feasibility of producing an easy to use, marketable global test in the arena of clinical hemostasis testing that is sensitive to antithrombotic drugs, bleeding disorders and thrombotic pathologies. This assay will offer significant cost advantages over current technologies by potentially replacing the need to perform multiple assays to determine an individual's haemostatic risk potential.